Abstract: A coating composition such as nitrocellulose lacquer or varnish incorporates a flatting pigment having non-settling properties obtained by grinding a dried precipitated hydrated silica and calcining it at a temperature between 400.degree. C. and 600.degree. C. so that the pigment consists of particles smaller than 10 microns in size having a bound water content below 2%. The calcination may be effected before or after the grinding. Advantageously, a wet precipitated hydrated silica is spray-dried to about 12% or less total moisture; the dried hydrated silica is milled and air classified to obtain material consisting entirely of particles smaller than 10 microns in size; and these particles are calcined at a temperature between 450.degree. C. and 550.degree. C. The pigment product so obtained exhibits outstanding non-settling flatting characteristics in nitrocellulose lacquer.

Abstract: A method for controlling the viscosity of dispersed clay slurries is disclosed. In accordance with the invention the problem associated with shipping or storing clay slurries in tank cars or tanks, that is, significant increases in the viscosity of the slurry which often results in the formation of a gelled mass, is overcome by the addition of citric acid. The addition of the citric acid serves to control the viscosity of the clay slurry in a manner such that it remains at a substantially uniform and low level even when the slurry is shipped or stored over extended periods of time. The citric acid is added to the slurry in relatively small quantities, i.e., up to 5.0 pounds/ton clay and unexpectedly does not affect the properties or characteristics of the clay pigment or product.

Abstract: A method for controlling the viscosity of dispersed clay slurries is disclosed. In accordance with the invention the problem associated with shipping or storing clay slurries in tank cars or tanks, that is, significant increases in the viscosity of the slurry which often results in the formation of a gelled mass, is overcome by the addition of tartaric acid. The addition of the tartaric acid serves to control the viscosity of the clay slurry in a manner such that it remains at a substantially uniform and low level even when the slurry is shipped or stored over extended periods of time. The tartaric acid is added to the slurry in relatively small quantities, i.e., up to 5.0 pounds/ton clay and unexpectedly does not affect the properties or characteristics of the clay pigment or product.

Abstract: A method for controlling the viscosity of dispersed clay slurries is disclosed. In accordance with the invention, the problem associated with shipping or storing clay slurries in tank cars or tanks, that is, significant increases in the viscosity of the slurry which often results in the formation of a gelled mass, is overcome by the addition of gluconic acid or a salt thereof, such as sodium gluconate. The addition of the gluconic acid or the salt serves to control the viscosity of the clay slurry in a manner such that it remains at a substantially uniform and low level even when the slurry is shipped or stored over extended periods of time. The gluconic acid or gluconate is added to the slurry in relatively small quantities, i.e., up to 5.0 pounds/ton clay and unexpectedly does not affect the properties or characteristics of the clay pigment or product.

Abstract: The amount of polycyclic aromatic hydrocarbons on the surface of a carbon black can be reduced below 2 ppb by heat treating the carbon black in a fluidized bed. Dried furnace carbon black pellets are charged in a fluid bed unit and preheated. The pellets are then fluidized with air, with the temperature of the bed between 1150.degree. F and 1850.degree. F for 5 to 40 minutes. The carbon black is then quenched and recovered.

Abstract: Method of agglomerating powders and non-flowing fine particle minerals such as clay, silicas, and silicates including the steps of establishing a minimum level of wetting agent content in the material to be agglomerated, tumbling the material to be agglomerated over itself within a rotatably mounted drum, adding additional wetting agent to the material within the drum, and removing the agglomerated powder, which is now formed into pellets of an advantageous pellet size distribution, from the drum. The wetting agent may be added by strategically positioned nozzles within the drum. The establishing of a minimum level of wetting agent content in the powder, preferably in the range of 11/2 to 5%, is achieved either by incomplete drying of the material during wet processing or by the application of a wetting agent prior to introduction into the drum.

Abstract: A method for reducing the viscosity and for refining crude kaolin clays is disclosed. The inherent viscosities of crude kaolin clay ores, particularly those having acceptable optical and purity properties for use in preparing paper coating pigments, but normally rejected because of their high inherent viscosities, are significantly reduced by contacting an aqueous slurry of the crude clay with an inorganic polymeric complex having the general formula[Al (OH).sub.y A.sub.3-y ].sub.xwherein x = 6 to 24, y = 1.0 to 2.75 and A is selected from the group consisting of Cl.sup.-, (SO.sub.4.sup.--).sub.0.5 and NO.sub.3.sup.-. In a preferred embodiment the above treated clay is also subjected to a high shear mixing action or kneading prior to further conventional processing procedures, such as fractionation, leaching, etc.

Abstract: Methods are disclosed to produce carbon black by diluting the concentration of reactive species by the addition of substantially inert gases to the reactive gas stream prior to the termination of particle growth.

Abstract: A new and improved discharge system for a spray dryer that permits the immediate exit of dry solids from the chamber of a spray dryer is disclosed. The spray dryer apparatus of the invention comprises a cylindrical drying chamber having a lower conically shaped discharge portion. The liquid or slurry is introduced into the drying chamber in the form of fine droplets which are contacted with a stream of hot gas that evaporates the liquid, leaving residual particles of dry solids. The solids are collected in the discharge portion of the dryer. The latter, i.e., the conical bottom is provided with a series of openings or slots near the bottom discharge outlet. Vacuum means, such as an exhaust fan creates a vacuum in the discharge outlet so that outside air is pulled in through the openings and the air conveys the solids immediately as they are collected. The solids in the stream of air are recovered by means of a gas-solids separator such as a cyclone separator.

Abstract: Apparatus for agglomerating powders and non-flowing fine particle minerals such as clay, silicas, and silicates involving means for establishing a minimum level of wetting agent content in the material to be agglomerated, a rotatably mounted motor driven drum for tumbling the material to be agglomerated over itself, spray nozzles located within the drum to add additional wetting liquid to the material within the drum, and conveying means for passing the material into the drum and discharge means for removing the agglomerated powder, which is now formed into pellets of an advantageous pellet size distribution, therefrom. The spray nozzles are situated to spray the wetting agent onto the material at the curl thereof. The establishing of a minimum level of wetting agent content in the powder, preferably in the range of 1-1/2% to 5%, is achieved either by incomplete drying of the material during wet processing or by the application of a wetting agent prior to introduction into the drum.